Numerical simulation of the Innoslab laser amplifier based on Yb:YAG crystal

A numerical simulation model is developed for a Yb:YAG Innoslab amplifier. By unfolding the multi-pass folded optical path into a one-dimensional slicing model, the model employs differential iterative calculations. This approach enables high-precision characterization of key physical processes, including spot size evolution, pump-laser saturated absorption distribution, the Yb:YAG reabsorption effect, and the spatial dynamic coupling between the pump and seed beams. Notably, a novel correction mechanism for the small-signal gain coefficient in the overlap regions of adjacent passes is proposed for the first time, specifically addressing the energy re-extraction issue neglected in previous models. This correction significantly enhances the computational accuracy and physical fidelity of the model. Validations against existing experimental data demonstrate high consistency between simulated and measured results, confirming the model’s excellent applicability and reliability. This work provides a reliable theoretical basis for the structural optimization and parameter tuning of Innoslab amplifiers.